Overview. Caffeine is a chemical primarily found in coffee and tea, but which also appears in various sodas, sports drinks and foods. It is a stimulant, therefore causing changes in metabolism as well as increases in focus and energy. Caffeine is addictive and can cause withdrawal following cessation after frequent use.
robot. 1  a machine that resembles a human and does mechanical, routine tasks on command. 2  a person who acts and responds in a mechanical, routine manner, usually subject to another's will; automaton. 3  any machine or mechanical device that operates automatically with humanlike skill.
noun. 1  1A machine capable of carrying out a complex series of actions automatically, especially one programmable by a computer. âhalf of all American robots are making cars or trucksâ. 2  2Computing. âWhat's good for the visitor is often good for the search engine robots.â. 3  3South African A set of automatic traffic lights.